Q  How do I change details of item(such as the description or the price)  in my Inventory?

There is a way to change details such as prices for things in the Inventory, if that is what you are certain you want to do.
 
This is a hidden feature that I don't want to broadcast to the world because, generally speaking, it can lead to problems.  Here is the procedure...
 
Go to the "Manage Inventory" option of the Inventory menu.  You will notice that in the bottom left corner of the screen there is an area/rectangle called "Item Details"  In this area/rectangle are details of the currently selected inventory item, like the item description, retail price, part number, In stock value, maximum, minimum and so on. You will also notice that only three fields are "enabled", or available to be changed. These are Stock/Hold (what you have on your shelf), Maximum and Minimum.  The rest of the fields are "disabled", which means you cannot click on them to change their values.
 
That is done on purpose because by and large, changing these fields could cause havoc in your inventory and, worse, could cause your orders to the company to be completely wrong. Having said that, there will be times when something has to be changed because of a error on my part (heaven forbid!), or a printing error on the Order Form I took the information from, or a situation of changed prices or practices that the DCMS wasn't prepared for.
 
In that case, you can gain access to the disabled fields by double-clicking on the words to the left of them. For instance, if you want to be able to change the price of an item or items, double click on the words "Retail Price" to the left of the (disabled)  price field in the Item Details area. You will note that the price field will become enabled and you can change retail prices in that field. When you leave and subsequently re-enter the Manage Inventory function, the field will become disabled again.
 
Once you have access to the field(s) you want to change, find your item(s) and change the details. Then close the Manage Inventory screen, and your changes will be saved.
 
Hope that helps.